Tracy and Leupp described twilight sleep as “a very fine balance in the states of consciousness,” which required “special knowledge of the use of drugs that cause it.” Once a woman had gone into labor, she was given a combination of morphine to dull the pain and scopolamine to dull her memory of the experience. (Today, scopolamine is sometimes called the “zombie drug” because its users become susceptible to suggestion but retain no memory of their actions.)

These drugs had been used in the past as anesthetics, but few doctors had adopted them with enthusiasm. But the German clinic, the McClure’s article reported, had reached a technical breakthrough with scopolamine, which allowed the doctors to administer it with more precision and therefore with more success. Women who they treated with these drugs would retain muscle control and would follow orders from doctors, but would remember none of it.

There were some strange conditions that went along with the use of these drugs. Because the women’s state of suspension was precarious, women in twilight sleep were kept in padded, crib-like beds, with eye masks blocking out the light and cotton balls in their ears blocking out sound. Sometimes they were fitted into straight-jacket-like shirts that limited the movement of their arms. When the birth was over, women also often experienced a moment of dissociation, as Carmody did: Had they really had a baby? Was the baby they’d been handed really theirs?